// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef MEDIA_AUDIO_ANDROID_OPENSLES_OUTPUT_H_
#define MEDIA_AUDIO_ANDROID_OPENSLES_OUTPUT_H_

#include <SLES/OpenSLES.h>
#include <SLES/OpenSLES_Android.h>
#include <stddef.h>
#include <stdint.h>

#include <memory>

#include "base/compiler_specific.h"
#include "base/macros.h"
#include "base/synchronization/lock.h"
#include "base/threading/thread_checker.h"
#include "media/audio/android/opensles_util.h"
#include "media/audio/audio_io.h"
#include "media/base/audio_parameters.h"
#include "media/base/audio_timestamp_helper.h"

namespace media {

class AudioManagerAndroid;

// Implements PCM audio output support for Android using the OpenSLES API.
// This class is created and lives on the Audio Manager thread but recorded
// audio buffers are given to us from an internal OpenSLES audio thread.
// All public methods should be called on the Audio Manager thread.
class OpenSLESOutputStream : public AudioOutputStream {
public:
    static const int kMaxNumOfBuffersInQueue = 2;

    OpenSLESOutputStream(AudioManagerAndroid* manager,
        const AudioParameters& params,
        SLint32 stream_type);

    ~OpenSLESOutputStream() override;

    // Implementation of AudioOutputStream.
    bool Open() override;
    void Close() override;
    void Start(AudioSourceCallback* callback) override;
    void Stop() override;
    void SetVolume(double volume) override;
    void GetVolume(double* volume) override;

    // Set the value of |muted_|. It does not affect |volume_| which can be
    // got by calling GetVolume(). See comments for |muted_| below.
    void SetMute(bool muted);

private:
    bool CreatePlayer();

    // Called from OpenSLES specific audio worker thread.
    static void SimpleBufferQueueCallback(
        SLAndroidSimpleBufferQueueItf buffer_queue,
        void* instance);

    // Fills up one buffer by asking the registered source for data.
    // Called from OpenSLES specific audio worker thread.
    void FillBufferQueue();

    // Called from the audio manager thread.
    void FillBufferQueueNoLock();

    // Called in Open();
    void SetupAudioBuffer();

    // Called in Close();
    void ReleaseAudioBuffer();

    // If OpenSLES reports an error this function handles it and passes it to
    // the attached AudioOutputCallback::OnError().
    void HandleError(SLresult error);

    base::ThreadChecker thread_checker_;

    // Protects |callback_|, |active_buffer_index_|, |audio_data_|,
    // |buffer_size_bytes_| and |simple_buffer_queue_|.
    base::Lock lock_;

    AudioManagerAndroid* audio_manager_;

    // Audio playback stream type.
    // See SLES/OpenSLES_Android.h for details.
    SLint32 stream_type_;

    AudioSourceCallback* callback_;

    // Shared engine interfaces for the app.
    media::ScopedSLObjectItf engine_object_;
    media::ScopedSLObjectItf player_object_;
    media::ScopedSLObjectItf output_mixer_;

    SLPlayItf player_;

    // Buffer queue recorder interface.
    SLAndroidSimpleBufferQueueItf simple_buffer_queue_;

    SLDataFormat_PCM format_;

    // Audio buffers that are allocated during Open() based on parameters given
    // during construction.
    uint8_t* audio_data_[kMaxNumOfBuffersInQueue];

    int active_buffer_index_;
    int bytes_per_frame_;
    size_t buffer_size_bytes_;

    bool started_;

    // Volume control coming from hardware. It overrides |volume_| when it's
    // true. Otherwise, use |volume_| for scaling.
    // This is needed because platform voice volume never goes to zero in
    // COMMUNICATION mode on Android.
    bool muted_;

    // Volume level from 0 to 1.
    float volume_;

    int samples_per_second_;

    // Used to calculate the delay value for each OnMoreData() call.
    AudioTimestampHelper delay_calculator_;

    // Container for retrieving data from AudioSourceCallback::OnMoreData().
    std::unique_ptr<AudioBus> audio_bus_;

    DISALLOW_COPY_AND_ASSIGN(OpenSLESOutputStream);
};

} // namespace media

#endif // MEDIA_AUDIO_ANDROID_OPENSLES_OUTPUT_H_
